Systems and method for a composite blade with fillet transition

1. A system, comprising:

a turbomachine blade segment, comprising:

an airfoil;

a platform coupled to the airfoil, the platform comprising a first side;

a concave fillet transition extending between the airfoil and the platform on the first side, wherein an outermost surface of the turbomachine blade segment has a smooth curvature corresponding to the concave fillet transition between the airfoil and the platform; and

an interface ply segment coupled to the airfoil and to the platform, the interface ply segment defines a first face and a second face opposite the first face, wherein a first portion of the first face couples to a first platform layer and a second portion of the second face couples to a second platform layer, and wherein the first or second face defines a corner that couples to an end surface of either the first platform layer or the second platform layer.

2. The system of claim 1 , wherein the airfoil comprises a plurality of airfoil ply layers, the platform comprises a plurality of platform ply layers, and the plurality of airfoil ply layers and the plurality of platform ply layers each comprises a first plurality of ceramic fibers distributed throughout a first ceramic matrix material.

3. The system of claim 2 , wherein the interface ply segment comprises a second plurality of ceramic fibers distributed throughout a second ceramic matrix material.

4. The system of claim 3 , wherein a density of the second plurality of ceramic fibers varies within the second ceramic matrix material.

5. The system of claim 2 , wherein the plurality of airfoil ply layers, the plurality of platform ply layers, the interface ply segment, or a combination thereof are secured to one another with at least one of a chemical bond or a metallurgic bond.

6. The system of claim 1 , wherein the turbomachine blade segment comprises a filler region defined by a space between the airfoil, the platform, and the concave fillet transition.

7. The system of claim 6 , wherein the filler region is filled with a plurality of ceramic fiber pieces, the plurality of ceramic fiber pieces suspended in a third ceramic matrix material, or a combination thereof.

8. The system of claim 1 , wherein the concave fillet transition extends from a tip of the airfoil to an edge of the platform.

9. A system, comprising:

a turbomachine blade segment, comprising:

a plurality of airfoil layers laminated to one another to form an airfoil;

a plurality of platform layers laminated to one another to form a platform, wherein the platform is coupled to the airfoil;

a first interface ply segment extending across an exterior surface of the airfoil to form a concave fillet transition between the airfoil and the platform; and

a second interface ply segment, wherein the second interface ply segment defines a first face and a second face opposite the first face, and wherein a first portion of the first face couples to a first platform layer and a second portion of the second face couples to a second platform layer of the plurality of platform layers to couple the airfoil to the platform, and wherein the first or second face defines a corner that couples to an end surface of at least one of the platform layers.

10. The system of claim 9 , wherein the plurality of airfoil layers, the plurality of platform layers, the first and second interface ply segments, or a combination thereof, comprises a plurality of ceramic fibers distributed throughout a ceramic matrix material.

11. The system of claim 9 , wherein the turbomachine blade segment comprises a filler region defined by a space between the airfoil, the platform, and the concave fillet transition.

12. The system of claim 11 , wherein the filler region is filled with a plurality of ceramic fiber pieces, the plurality of ceramic fiber pieces suspended in a third ceramic matrix material, or a combination thereof.

13. A system, comprising:

a turbomachine blade segment, comprising:

an airfoil;

a platform coupled to the airfoil, wherein the platform comprises a plurality of platform layers; and

a concave fillet transition extending between the airfoil and the platform; and

a plurality of interface ply layers extending between the airfoil and the platform, wherein each interface ply layer of the plurality of interface ply layers defines a first face and a second face opposite the first face, and wherein at least one interface ply layer of the plurality of interface ply layers is partially overlapped on both first and second faces by the plurality of platform layers, and wherein the first or second face of the at least one interface ply layer defines a corner that couples to at least one of the platform layers wherein an outermost surface of the turbomachine blade segment has a smooth curvature corresponding to the concave fillet transition between the airfoil and the platform.

14. The system of claim 13 , wherein the plurality of interface ply layers comprises a plurality of overlapping interface ply layers, a plurality of non-overlapping interface ply layers, or a combination thereof.

15. The system of claim 13 , wherein the plurality interface ply layers comprise three or more interface ply strips each extending across and between a first exterior surface of the airfoil and a second exterior surface of the platform, and the three or more interface ply strips extend across different portions of the first and second exterior surfaces.